Train-control system



Jan; 7 1930. A H, ADAMS l,742,1s9

TRAIN CONTROL SYSTEM fw, "f

Www/k. y Af/fw Jan. 7, 193W A.- TT. ADAM@ TRAIN CONTROL SYSTEM Lmmw m16@ April 22, 192e 5 sneetsneet 2 l'criar/avv SPEED L/M/T/NG occUP/ED SPEED ./M/T/NG RECORDING STR/NG Jan. 7, 1930. .A. H. ADAMS TRAIN CONTROL SYSTEM Filed April 22, 19a .'5 SheecsShe-et 5 Nrv MMM/W A M M d, Q ww i ,i a... .I tratenteui dan. a, .iiddtt TRAIIliF-CGNTBUL SYSTEM Application led April,

y AThis invention relates' to train controlsys- Atems, and more particularly to that class of systems `n which indications governing the progress of a train are continuously received o on the train.

lt is the object of 'the invention to provide new and improved means for indicating the speed atwhich the train should move during certain trafiic conditions, e. g., in a stop or io occupied7 block, and to control the automaticapplication of the brakes if a predetermined speed is exceeded. I

ln accordance with the present invention this is accomplished-byproviding on the train a timing device which operates at a predeter mined rate of speed. `Means, preferably in the 'form oit' a recorder, are provided for comparing thespeed of the train with that oi the timing device and for preventing the auto- 23 matic application otbrakes as long as the train proceeds wit-hin 4the predetermined speed limit. As soon as this speed is exceeded,- the recorder is operated to permit the automatic applicationrot the brakes. I

ln accordance with one of the `features of the inventionthe recorder consists of counting relays which are operated in .one sense by an interrupter mounted on the axle of the locomotive7 4and vin thevopposite senseby the timing device. Means are `provided forl visually indicating to the engineer that he exceeds the allowed speed. The engineer is thus given anopportunity to forestall the automatic application oi the brakes. The invention is illustrated in connection with an inductive receiver of a continuous iniuence system, described and claimed in my copending' application Serial No. 610,804, filed January .5, 1923, but it will be obvious to 43 those skilled in the art that it is capable of various other applications without departing from the spirit thereof. I

ln the drawings, Fig. l represents a block or section o-track insulated from adjacent i5 blocks with a diagrammatic showing of a controller for producing codes ot impulses in the track and with a diagrammatic representation oi' a locomotive in the block;I Fig. 2 represents one type of current wave form that may be produced in the track and the coriaac. serial no. ioavaaw responding voltage wave formL induced in the receiver; Fig. 3 represents anotherform of y track wave,A and the correspondingvoltage wave form in the receiver; Figs. 4-9 are schematic` representations of various codes that may be used; Fig. 10 is schematic illustra. tion of as much of. a simple form of receiving apparatus and receiving circuit onthe loc'o- 2 motive as is necessary for a clear understanding of the invention by one skilled in the art; oo and F ig. 11- is a schematic illustration offene form of the'track code controller symbolized or dagrammatically shown at 3 and 6 of Fig. l. f

ln Figi l, l are rails bonded to form each a continuous conductor Viir'om end toend. 2 are insulators electrically separating the rails of the one block from adjacent blocks., .3.is' a cireuitconnection between the two rails at the entering end of the block and will usually comprise a relay or relays'for signaling and other purposes. 4, as indicated, is a symbol for a locomotive carrying,`\aheado;t the front wheelsz .inductors 5, more clearly shown in Fig. 10 in their relation to the rails l. 6,'as indicated, is a track currentcontroller. Its' function is the setting up of suitable codes of impulses in the rails of a block' as determined by the condition of the track ahead. As is well known, such controllers comprise a source of electrical current, either'in the form of a generator or battery, Vor in the form of power linesfrom a distant source of current supply, and an interrupter, switch, polechanger, reversing device, rheostat or the like, for making, breaking, reversing or otherwise varyingfthe current flowing in ay given circuit. Reasonably reliable speed controlling or time-measuring means is also comprised in any such controller. rllhe controllery 6 needv not even be situatednearthe-track, but the conductors connecting it thereto may be extended so that one controller may serve a number of sections of track. The connection between the controller and the track circuit maybe inductive, as through a transformer, instead of conductive as illustrated. ln fact, any vwell-known means may be used to produce a current flow` in the track ont the character described. Merely to tix the ideas, a

suitable controller and a cooperative track relay are shown in Fig-11 and will be detal dimensions represent time and the vertiscribed below.

The upper line of Fig; 2 is a graph or.\ current-change curve in which the-horizon cal dimensions above the line -0 represent itive current, and the vertical dimensionsl elow the. line 0-0 represent negative c'urrent. The lower line of Fig. 2 shows the corresponding voltage for the receiver and the two, together, illustrate howfa gradual increase of current in the track induces-a very small, steady voltage in the receiver, and

vhow the abrupt dying out of the current in reversals of current direction in the track induce inthe receiver relatively strong but brief impulses corresponding in sign to the .track impulse.: A i Y Fig. 4 symbolizes a preferred code of track impulsesfor we may read them as detected in the receiver) which will permit a locomotive carryin vthe receiver of Fig. 10 to travel at any spee at which the engineer may def sire to run without automatic interference.

. This code I, have termed the clear or unlimited code; In this figure and in Figs. -9 inclusive, horizontal dimensions represent, in ageneral way, time; lthe signs -land abovel and below the line O-Ovreprewhich-is readilyv done by adjusting its armature nearer to one pole than tothe other so that said armature has a normal position ofy rest when no current is flowing through coils 21 and 22 and does not, as I prefer it to do,

Aremain on either side according to its lastv operation, then the clear code may be composed entirely of impulses of one polarity.` Such impulsescould be of the type of the positive track and receiver impulse forms of Fig. 2. They would have to be repeated at intervals sufficiently brief, i. e., at intervals not exceeding a time A found suitable to properly operate the receiving circuit.

Fig. 5 illustrates a codeof impulses which, in cooperation with the receiving apparatus and circuit (Fig. carried on the locomotive, will act to prevent the engineer from continuing at a speed higher than a certain predetermined limit when the locomotive is in a block in the rails of which this code is being produced. While the details of the receiving, circuit may be modified in many ways, in the disclosed receiving circuit the code'of Fig. 5 will automatically apply the brakes under certain conditions within a brief period after this code has begun to act upon the receiver. One` of these conditions is that the train be moving faster than la 'certain speed. Another is that the engineer has not by a manual' application of the brakes valready started to reduce the speed of his train. The above is merely explanatoryof the function of this code of Fig.- 5 and the detailed conditions and operation willv be more particularly described below.

sent each one an impulse of positive or neg- This code and those having the-same general ative polarity and are `with equal logic in most cases understood to symbolize eitheror 4boththe impulses in the. track or in the receiver.

In the code of Fig. 4, clear code, it will 'be seen that the time represented by the dimensions` A is relatively brief between each impulse and, the'next effective one. In this case, and because an unbiased polarized relay is utilized, the next effective impulse is the next of the opposite polarity. Without limitation to any definite value for this time and merely to fix'the' ideas, this period may be of the order of one second. It ymustbe understood that while this code is the only Fclear.V code illustrated and is the preferred 'speedllimiting function are herein generically termed caution codes. It will be observed Vthat the time Bin the code of Figs. 5-8 isthe longesttime between effective ,i-m-

pulses. With an unbiased vpolarized receiv-I ing relay, the time between ...effective iinpulses is ,the vtime from the first'impulse of one polarity to therst of the opposite po-.

larity. Time B is several times lon er than the time A of the clear, code. fix the ideas, we -may'taketime :B as of the order of seven seconds. It should be noted that one of the merits of timed impulse times B may be largely varied according to the speed limit desired by different railroads, in different portions of one railroad,in different blocks behind an occupied block, even if desired, atdifferent times of the day or of the year, or for other reasons as may be dif'- tated by experience.

With a biased polarized receiving relay this code might equally well be composed'of nothv ing but positive impulses, e. g.. of the type of Fig. 2, occurring lat proper time intervals B. No clear or cautioifcodes of this type,

i. e., composed solely of impulses of one polary ity, have been illustrated in the drawings for erely to l codes for controlling train speeds is that the the reason that the polarized relay 23, shown is pointed out here merely to emphasize the ,fact thatthe intervals of time between effectively received impulses are the most important. distinguishing characteristics of these dilerentcodes.

rig. ennemies a caution tde identical with ,that of Fig. except that the tirst posi- 'tive imp ulse induced in the receiver is .suc-

ceeded by a series of positive impulses having `no'etlect 4vvhatsoeveron the preferred receiver, and the lirst negative impulse is likewise succeeded bynegative impulses Without eiiect.` This variation is illustrated to show the flexibility of the system, and, whileof no advantage in the practice ot this present invention as shown, might be preferable to that of Fig. for use in connection witlertain` types of track current control or local signalingcircuits or with certaintypes of trackrelays.,y Thus i-pthe ltrack currentchngefcurves of Fig. 2 are used, the code of Fig; jvvouldinvolve a relatively long time' .withno 'iurrent in the railsrl and through the connection'ort'rack relay 3. It We sup- ',pos'e 3 to bea signaling relay requiringto be held ,up during the caution7 code, track impulses of the form ot'Fig. 2, repeated as in the code' of'Fig. 6, might, With certain types of relays, more readily accomplish this end for the signal engineen The relationships between theA codes in the one block and.

in the block behind Vor before and the means of producing these relationships may be greatly varied Within the spirit of this inven tion. The-above remarks as to the possible superiority of .the code of Fig. 6 under certain circumstances are merely illustrative of the inherent flexibility 4ot" the present track` current code system.

Fig. f7 illustrates a. third caution codo in which the time B, as before, is the period from the occurrenceofthe first impulse in the receiver oone polarity untilthe occur-` rence'of the first. of the opposite polarity. Itdiffers from the codesjof Figs. 5 and 6 in that'a brief period Av is interposed bctween the longer periods B, and 4is typical ol' a Whole class of possible, butnot further illustrated, codes in whicli periods of clear code are regularly interruptd byrelativelyl long` caution7 periods or code pauses B.

Fig. 8 illustrates a code identical with; that of Fig. 7 except thatthe polar-ities are reversedand 'with the Vfurther exception that the times B are filled with repeated impulses of the one polarity after the manner of the code of Fig. 6.

Fig. 9 illustrates three ot the manypossible` varieties of vstop block codesV and a fourth code or condition of an occupied block. In

the present disclosure there are. provided mean'svvhereby low speed running, limited to perhaps 10 or 15 miles an hour, is permitted in an occupied block and also in the block, termed a stop block, just preceding any occupiedlblock There are, in a stop block codes. However, to distinguish from the codes of Figs.. 5, 6, Zand '8, tliey are herein referred to as, occupied ande-stop codes. And because the receiver-of'Fig. 10 does not differentiate between the stop and the "occupied codes, the same Ilow'speed limit in l this illustrationl of my invention applyingr to both, the following description of the'operation of the receiver refersto these codes Vonly as occupied codes.

The one essential characteristic thatthe four Vcodes illustrated in Fig. 9 have in common is that, with the exception of asingle first impulse in several cases, thy produce no effect whatever upon the receiving relay. They are,

to all intents and purposes, the same in eiect Von the receiver of Fig. 10 vas long code pauses B of the various types'shown in the caution `codes of Figs. 5 8. The second code'shown in F1g. 9 is a series'ofr'epeated-negative impulses. The third shown is a longcontinued 'direct current flow in the track ina positive direction, i. e., an indefinitely extended wave oi the type of the track wave of Fig. 3. A

continued flow 'in the negative direction in the track would be another possibility. The' 'fourth code shown in Fig. AQis'merely dead track, i. e., without current o iany kind. 'This is the code or condition in an toccupied block behind the occupying train .or vehicle. Ob

viously, the third and the fourth-,are identical as far as the impulses induced inthe receiver are concerned, and 1it will be seen when the receiver circuit of Fig. l0 1s descr1bed,`tbat all tour are identical as tar asetlectsonvthe polarized receiving relayv are concerned.

The advantage of the last two codes will bev .i

particularly apparent when it, is considered that failures of the source of track energy S of Fig. l, the failure of the track current controllerv of Fig. l, the openin of the track circuit or the short-circuiting t iereof, at any point between the locomotive@ and the controller 6, all act to produce this form oli code.

Likewise, any failure of the-receiving uit. M.l1-

anism of Fig. l0 to receive the impulses. that I may be in the track has the same leffect or he train control mechanism as these last two codes. lThere is asimilar advantage in the choice of the lirst twocodes illustrated vin' Figi),l in that any failures 'in the track current controller at'ecting one polarity only,

or anyfailures in the receiver of Fig. 10, such vi'ous.

:--In Fig. 10, 1 are the rails of Fig. 1 shown in cross-section, 5 the inductors 'or vinductive receivers each comprising an iron cdore mounted on the locomotive in a position as near to the rail as the necessary clearances ofrail,- road usage will'permit. These cores`are each surrounded by a winding 7 and these tw'o windings are preferably connected in series,

and also in such a manner that the electrometive forces', generated in the windings .7 by changes of current in the rails 1, shall reinforce each other. The relative directiolrof operation of this receiving structure has been described, a very refined and Aexceptionally quick design for the left-hand quick-acting slow-,releaserelay 34 would, in this event, be required. As stated above, the biased polarized relay would be less sensitive. The changeoHers no suicient advantages over my preferred structure so far as I can perceive to compensate for these two4 disadvantages. It

is possible again, as stated above, that* for cer. f y tain track circuit purposes a code of one polarity would be a simplification. Y Resuming the description of the structure ux in the two inductors, when the 'current' ini-.ras shown, the iiux due to currents inthewjndthe track circuit is in one direction, is indicated by arrows on thedotted lines 8. From the inductors two conductors 9 and 10 lead respectively to the filament and 4grid of a three-electrodeelectron tube 12. 11 is a lilay ment heating battery or .s0-called A battery; 13 is the plate circuit battery usually called the B battery. lThe plate circuit is completed by conductors 14 and`15 through the primary 16 ofa transformer. 17 is the iron core of this transformer. 18 is thesecondary; conductors 19 and 20 complete the secondary circuit through thewindings 2l and 22 of a polarized relay 23. As illustrated, this relay is electromagnetically polarized by energy from a battery 24 and a polarize ing winding 25, but a permanent magnet may be used in placeof an electromagnebas a source of polarizing flux. The windings 21 and 22 are wound andvconnected in such a manner that a current fiow in either direction in the secondary circuit 18` 20, 22, 21, 19 tends to produce opposite olarities at the poles 26- and 27. The polarizmg Hux due to the winding 25 enters the armature 28 substantially at the center and a portion goes to the righthand half of the armature returning through -pole 26 and the common frame 23 of the relay.

A portion of this polarizing flux goes to the left-hand half of the armature through pole 27 and returns through the lcommon frame 23. Thus the flux due to the polarizing coil is in the same direction through both poles 26 and 27. The preferred adjustment-of the relay is such that the pull of these two poles is substantially equal when tongue 29 is held half-way between its two positions of Contact with conductors 31 and 32.

At this point it may again be mentioned that if the relay were such that tongue 29,

when no currentflows in coils 21 and 22,.al ways returned to lie on the same side, it would respond only to impulses of one polarity. It we assume that it lies as actuallyy shown in the ings 21 and 22 being of opposite-sign the two poles, opposes the polarizing flux in the one pole and aids it in the other. Due to the well-known law that the pull between a po e and an armature is proportional to the square.

.of the average density ofthe iiux, multiplied lby the effective .cross-section ofthe iiux, this type 'of relay can be made responsive to'veryand which makes contact in the one position with conductor 31, in the other with con-y ductor 32. AThis armature is pivoted on a knife edge 33 and, in the absence' of current through windings 21 and 22, retains the contact which it last made with some firmness due to the polarizing flux which holds the ar-v mature strongly to the nearer one of the poles 26, 27. In thediagram more polarizing flux is temporarily passingV through pole 27- than throughpole 26 because of the temporarily larger air-gap at pole 26. The tongue29 is ,therefore lirmlyheld in contact with conductor 31.

Polarized relay tongue 29. due to received and amplified `impulses of alternate polarity, closes the circuit alternately from ground 30 'through conductor 31 or 32 and either one of two quick-acting slow-release relays 34 to battery and ground. Relays 34 may be of any suitablehconstruction well known in the art but are very simply and preferably made of the simplest D. C. relay form, with the addition of a heavy copper collar or sleeve`35 which, acting as a short-circuited secondary, Arenders the action of the'relay sluggish, more especially on releasing. Byv a suitable adwaaien close a series circuitfrom ground through the twoari'natures 36 and their two front contacts 37, conductors 38 and 67, the extreme lefthand contacts of relay e and IC, conductor 39, and in multiple through the left-hand windings of relays 40 and l, to battery and ground. A'branching circuit 4l from conductor 67 includes a green signal lamp 42 normally in parallel with the left-hand windings ot relays 40 and I. 4

Relay 40 is shown with two armatures, but this is done for simplicity' in the diagram This relay and those like it in the drawing are preferably of one ot' the well-known l). C.

types having an armature closing, when ener- For brevity l shall hereafter refer to the right and lett-hand armatures just as shown in the drawing. Relay 40 has a right-hand winding connected (aiding the lelft-hand winding) through the right-hand armature when 40 is energizedand then through conductor 43 to' a y wiper 44 which bears on an interrupter 45.

Interrupter 45 has a relatively short insulated segment anda grounded conducting segment.

It revolves in a clockwise direction as viewed inthe drawing and is carriedv by or operated from a wheel or axle of the locomotive.

substantially 18()o distance from wiper 44 and connects ground to certain relay armatures through conductor 47, as will be explained" The left-hand armature-ofrelay 40is.'

of which the circuit is closed from. the grounded interrupter 45, through wiper`46, conduce tor 47, and its own left-hand arma-ture to grounded battery, when relay Ois energized. This circuit is, of ccurse,'open at the interrupter when wiper 46 isv on the insulating segment. The right-hand armature of relay 50 is grounded and, when 50 is energizec closes a circuit containing the left-hand winding of relay 60. The relay has a right-hand winding, the circuit of which is closed when it is energized, through its own right-hand armature, conductor 43, wiper 44 and grounded interrupter 45. This circuit is, of course, open at the interrupter when wiper 44 is on the insulating segment. lThe lefthand armature of relay 60 is grounded and when .energized closes a circuit containing the right-hand winding of the nent counting relay (not shown), and so on t'or an indefinite culnbcr. of relays. The .number ot these relays to be used7 which l have termed Jthe second wiper 46 bears on .interruptor 45 atcounting relays of the caution speed-limiting string or series, 1s dependent on the speed limits to be enforced and the length chosen for the code auses or caution intervals B.-

' For sinip ici'ty in the drawings ll have shown of this first string or series of counting relays only the first three designated 40, 50, 60, and the last three designated m, y, e. It

l will be clear from a comparison ofthe figures on the drawings that the relay as is connected exactly like the relay 50, the relay y is connected exactly like the relay 60, and the last relay .e again like relay 50.

Relay :c is energized through its right-hand winding by the let'tshand armature of the preceding relay and is periodically energized through its left-hand windingv by its own lefthand armature and the wiper 46 of interrupter 45. lThe grounded right-hand armatures of relaywv close, when the relay is energized, one additional circuit 'throughf conductor 49 and yellow signal light 5l, to grounded battery 4and a further circuit through conductor 491 and red signal light 51, to'grounded batter-y. Relay e is, by conductor 68, connected to the first relay 40a of a second or continuation series, which l have termed the time of grace recording string of relays, ust as relay 50 is to 60. ltelay 40a is succeeded by an. other relay (not shown), and so on to thelast relay zu. For simplicity ofthe diagram only the first-and the last relays 40a and .ea are shown of this second or time of grace series.

A further set of counting relays LII, HI I, Ib, I, is providedfor the purpose of limiting the speed of the train within an oc-4 cupied or stop block by comparing the speed at which the axle revolves with the speed .of a

constant-ly operating timing device provided in the'cab. The timing device is diagram-4 matically illustrated at T. Itconsists ot a constantly rotating intcrrupter provided with a short grounded 4segment whereby during each revolution ot the device ground is connected for a short period of time to a wiper z". The timing device should be protected against tampering. A'grounded interrupter 45a is mounted on the axle in substantially the same manner as interruptor 45, this interrupter cooperating with wipers 44LL and 46a to control the associated set of counting relays. 'The' interrupter 45a is` provided with any desired number of interrupter segments so as to deenergize a predetermined .number of counting relays during each revolution of the axle. 'the counting relays l to lc are placed under the control ot the interrupter 45' at the saine time that the relays 40 a are placed under control of interrupter 45, i. c., upon deenergization ot either slow release relay 34. The number of interrupting segments ot interrupter 45 and the number ot relays in the string ll l is'so chosen that,

when both strings 40 z and l lt are re leased' to the cuntrol. ottheir respective inter- .rupters,'the latter string will be 'completely -trol is in multiple with the control by the.

i right-hand armature of relay e. Thus relay 40" does not release when its right-hand coil is deenergized by the insulating segment of Ainterrupter 45, brush 44 and conductor 43,

unlessand until both relaysz and 1 are released. l

The circuit from ground through the armatures36 and contacts 37 of slow-release relays 34,' conductors 67' and 39 Vto the left-hand windings of both relays 40 and 1 to grounded battery, passes through two contacts'in multiple, these being the contacts of the extreme left-hand armatures of both relays e and 1.

Timer T, when revolved to the position where wiper t is on the grounded segment, establishes a circuit through conductor 80, `the extreme right-hand armature of relay 1c and its contact, conductorr79 and the righthand winding of relay 1 to grounded battery. By this circuit, timer T at regular time intervals cnergizes relay 1, whichenergizes relay 11,'etc.,l and thus energizes the whole string. 1f, however, the last relay, 1, is released when T is electrically connected with t, the circuit is broken between conductors 80 and 7 9a and lthen timer T eannotreenergize relay 1 or any of the string 1 1c.

This is similar i-'nv function to the means above described wherebyi the release of both the end relays@ and 1 opens the circuits through'which the slow-release relays 34 are able to reenergize relays 40 and 1, that is to 1t is assumed that a reduced pressure in this.

say, both strings of relays.

.- Relay za by its grounded right-hand armature and contact holds energized the solenoid 53 over the circuit .including conductor 52, the winding of 53, solenoid locking spring 54, conductor 55, to grounded battery:

The solenoid 53, while energized, maintains the Valve rod 56 and valve 57 in the upward position shown. 58 is/the body of an electropneumatic valve which comprisessolenoid 53, valve rod 56 and valve 57, and is shown in section. 59 is an ai-r pressure connection `from the brake-controlling air-line of the train.

air-line applies the brakes.- 61 is a tension spring to assist gravity in opening. the valve 57 when solenoi 53 is deenergized. 62 is a manually operable key for closing the circuit of the solenoid when it is deenergized and when in consequence spring 54 is not in contact-with conductor 55. Numeral 68 indicates direction of current iow in the track.

from ground through conductor 65, through' the left-hand coil of relay y to battery. Thus 64 is an alternative to and in multiple with the right-hand armature of' relay Spring 64 also closes a circuit through conductor 65 ,and the left-hand winding of relay 1b to grounded battery.- Thus, in relation to relay 1b, 64 is an alternative to and in multiple with the righthand armature of relay 1a. 66 is a sealed receptacle or box enclosing the electropncumatie valve, the solenoid 53, the key 62 and preferably, also, enclosing the pressure gauge contact elements 63, 64,. This receptacle or box and its seal may'be of any well-known construction. 1ts purpose is to preventv the engineer from closing the electropneumatic valve, if it once opens, without leaving proof that it has been open.

Assuming the locomotive 4 to be receiving.

the clear7 code of Fig. 4 or any equivalent code comprising continuous, sufficiently rapid, alternations of positive and negative impulses in lthe track, the operation is as follows: The current flow in the track, whether gradually increasing as diagramined ,-in thc upper line of F ig. 2', or steady as in windings 7. 'The abrupt interruption, or interruption and reversal, Iof the current flow in the track causes the sudden dying out ordying out and reversal of the flux 8. This sets up in windings 7 a relatively high electromotive force, the relative instantaneous polary ity of,which is dependent upon the original The eleetromotive force raises or lowers the potentialof the grid of the three-electrode electron tube 12 and causes a corresponding sudden increase or decrease in the plate current flow' frombattery 13 through filament and plate of 12, conductor 14, primary winding 16, and conductor 15. It will be noted that, .as is well understood by 'those skilled in the art'of amplification by electron tubes, this current will vary in magnitude but not in direction. -By the use of, the transformer elements 16, 17 and 18, these 'sudden increases 'and decreases-ofthe plate current are again converted into* .positive and negative impulses in the circuit '18, 19, 21, 22, 2O.4

yAs explained above, these positive and negative impulsesthrough the windings 21 and 22 of the polarized relay 28 throwA the contact tongue 29 from side to side, alternately' energizing relays'34. Relays 34 are designed to maintain their armatures attracted for a briel period after the circuit of their windingsis open and this period must be-someion llO

maare@ 'what greater than the period betweenalternate impulses of the code of Fig. 4 or any equivalent clear code that may be used. Relays 34 are also designed to attractltheir armatures 3G in a period somewhat lessthan y theperiod A. Thus when the code of Fig. 4

or an equivalent is beingproduced in track 1,- and when inconsequence tongue 29 of of relay e and Ic, conductor39, and left-hand windings of relays 40 I, tofbattery. 'The green signal light burnssteadily and, relays 40 and I remain energized. Relay 40 by its left-hand` armature maintains relay energized.A Relay I by its left-hand armature maintains relay II energized. Relay 50 by its right-hand armature maintains relay 60 energized and soitocthe end of the caution series, all the relays 40l to 'e remaining energized. Relay II maintains relay III energizedand so to Athe end of the occupied series, all the relays I tov IC remaining ener- 'gized One o'f the right-hand `armatures of *relay closes the circuit of the yellow signal lampv 51, which burns steadily.v Relay a, by

its right-hand armature, and realy Ic by its right-hand armature, maintain closed the circuits, includingconductor 68, oit the lefthand winding'of relay 40a. Relay 40 holds energized the next relay and so on toY relay ea, which, by its grounded right hand armature and through conductor 52, maintains solenoid 53 energized-*through spring 54 and conductor 55 to battery.v Solenoid 53 holds closed the valve 57 and air from the brakes cannot escape from valve chamber 58. Re-

"lays m and Ia both, by'their'right-hand arma-Y tures, keep red lamp 51a lighted.

The only moving elements in the circuit onv the locomotive under these conditions are the armaturegjzind tongue -28 and 29 of polarized relay 23,"the continuously revolving interrupters 45 and 45 connected to a locomotive wheel, and the timer 'l. rIhis may be called the normal or locked condition ot' the receiver.,

Assumingnow the'locomotive to be on track containing the cautlon or speed limit- A ing code of one of the types illustrated in Figs. 5-8 or equivalent, the operation is as t'ollows: l M y @mitting the repetition of the detailed operation ot receiving,vamp liiying and transforming 4the impulses, it will be elear from' be positively thrown to one side or the other insulating segment of 45.

onto an insulating segment of 45a. 'II is then unlocked and deenerglzcs one wind- Vdeene'rgized in the caution code and willt-here remain until the end-ot the l period B. The periodB is much longer than the period during which relays 34 can,A withoutcurrent in their windings, maintain their armatures attracted. @ne of these relays 34 will, therefore, after the lapse of a time somewhat greater than A, release its armature and open the circuit both of the green lamp 42 and of the left-hand windings of relays.

40 and' I. The green lamp will go out. Re-

lay 40 will be maintainedy energized by its rightdiand winding for a period varying from zero to nearly the time o-f acomplete revolution of interrupter. 4,5, but clearly will be deenergized when-wiper 44 goes over the Relay 40 will then unlock itself by its right-hand armature so that it cannot be again reenergized bythe `circuit from the ground through wiper 44 and conductor 43. 'Ih'e leftfha'nd armature of relay 40 being released, deenergizes theA right-hand winding of relay 50, which remains .energized by its left-hand winding until wiper 4G, in its turn goes over the insulating segment of 45. Relay 50 is then unlocked and deenergizes one winding of 60 which is next unlocked by interrupter 45, 'one-halt1 revolution later, and. so on. Simi larly, relay I will be maintained energized by its right-hand winding for a period varying from zero to nearly the time oi'a third of a revolution of interrupter 45a, but will be released when wiper 44a goes over the first insulating segmentot 45". Relay I will then unlock itself by its right-hand armature s that it cannot Abe reenergized by the circuit f1 'from ground through interrupter 45a and wiper 44a.A The release of relay I deenergizes the right-hand winding of relay II, whichremains energized by itsA left-hand winding. until wiper 46, in its turn, comes Relay ing o1" III, which is next unlocked by interr-upter'45a one-sixth' ot afrevolution later,

and so on. y

rlhe relaysl ot' the two series are thus un- `locked one' after the other at intervals measpeed in 1.-

R,- should also in all cases deeizergize relays :i

result is obtained by so' choosing the number of the relays I Ic and the number oit interrupting segments in 45" that, at any given s need, the time of counting down the string 1 is less than half the time of counting down Athe string e.. That this accomplishes the result will be evident from the following facts and reasoning:

At the limit of speed permitted in an occupied block, i. e., ata speed very considerably less than the maximum speed ermitted in a caution block, the time o counting down the relays 1. 1 is just barely greater than the time between pulses of timer T. This latter time is a constant. The action of timer T is discussed below. From this fact it follows that at the' speed assumed, excessive for a caution block, the time between pulses of timer T will be materially i greater than the time to countdown the rel,

-lays1...1.

Since this counting' down time is less than half the counting downtime of 40 e, it does notmatter where a pulse from timer T occurs, if any. For if one docs not occur within the first halfof the countingdown time of relays 40 e, then relay 1 will be released, severing the connection between conductors 80a and 7 9andrendering the timer pulse ineilective to reenergize 1 1 when it does occur. On the other hand. if the timer pulse occurs at some ins'tant within the first half of the counting down time of relays 40 e, restoring all the relays 1 1, then there will remain time enough thereafterfully to count down again the relays 1 1. Moreover, the next' pulse of timer T will not occur before this 1s accomplished, because at the speed assumed (a speed excessive for a caution block), the

semaphore, if there, is one, and has likewiseV not seen the extinctionof the 'green signal light in the cab of the locomotive and acted promptly, then relay at, which is the second from theA last relay of the first series, willrelease .its right-hand armature, extenguishing the yellow signal light 51 andthe red signal light 51.` This red light is multiply controlled, by the righthand armatures of relays :aand 1, but, as just proven, relay 1a will at this time have been released. Relay y and relay z are'next unlocked. Relay z, by its extreme left-hand armature, opens the connection between conductors 67 and 39. -This connection, as just shown, is already open at the left-hand Contact of relay 1.

This effectually' prevents the next track impulse, at the end of the. caution code interval B, from reenergizing .the relays 40 1n other words, if relay ais deener` gized under the conditions of excessive speed in a caution block, a brake application becomes unavoidable.

1f the engineer did not applyV the brakes when the green lamp went out, he should do so at once whenthe yellow andvred lamps go out. Should he fail to do this also, then the string of relays 40. Z, that 1 term time of grace relays, will be released one after the other, and when the last relay Za is released, the solenoid 53 is deenergized, opening'the electropneumtic valve 57, reducing the air line pressure and applying the brakes. However, if the engineer at any instant before the time of grace is exhausted, i. e., before relay Za' is deenergized, has made an effective brake application so that the air line pressure is reduced suliiciently to cause member 63 to press contact 64 against conductors 65 'and 65, there is a circuit established from by the energization of the deenergized slow-l release quick-acting relay 34, isable to restore relays 40 and 1 and hence to restore both strings ofv relays 40 .e and '1 1. l

1f now, being in a caution block, the engineer kee s on his brakes until his spoed is within. al owed limits, the interrupter 45 will not release the relays 40 e before each new track impulse-restores them. ,He should, in fact, keep on the brakes until relay is never released. `1t will be noted that while the speed is being brought down to the required limit for a caution block, relays 34 are operating and releasing alternately causing' the successive operation and release of the chain 40 40". The yellw and red lamps therefore flicker each time this string of relays is counted down. When the allowable speed is reached relay remainsoperated. The yellow and red lamps will then burn. steadily, and

he may then take off his brakes. AtI this time, and at all timesin a caution block, his green light will Hash up once every caution cycle, i. e., at time interval B.

1f the engineer failed to make a manual. ap-

plication of brakes before his time of grace 4relays were all released, and if therefore relay Z' releases solenoid 53 and causes an automatic brake applicatlon, the same circuits sacarse are closed that are closed by a manual appli. cation, namely, from ground through contact" (il, conductors 651 and 65, and the left-hand coilsfof relays y and lfb, to grounded battery,

lll

' and the restoring'circuit is made readyvvherethe brakes Without unsealing the boa, But by a manual application ofthe brakes,1i.' e., if just before relay'Za land solenoid 53 are deenergized, the circuits from ground through (il, through 65 and 65 and the right-hand windings of relays y and ll to battery and ground are closed, thedeenergization'of the solenoid will be forestalled and he vvil'l not have to open the born" Instead of pne'un'iatic,pressureW or other pneumatic meansfto close the contacts 6l, 65 and 65a when the brakes are applied, ,any Wellknown or obviou's'i mechanical, electrical or other meansmay be employed This is a matter in which the nature of the braking system inuse will be controlling, and one that vvill oil'er no difficulties tothose skilled in the art. As stated above, contacts (il, and thev connecting Wires and 65a are preferably located in sealed box 66. lltmay be more convenient to locate them elsewhere. '.lhey should be so de vised as not to be operable except by a brake application of. predetermined force or greater, and not to be accessible for tampering' lltMWill benoted that a small margin of safety'as to speed is provided by connecting lamps 5l and 51EL to relays one or two earlier I in thetwo series than the end relays a andllc. lf, Without this margin of safety the engineer should unconsciously allovv the train to speed up a very little, he might receive an automatic application ofthe brakes which would not be heralded by brief extinctions or' idiclrerings of red and yellovv lamps 5l and 5in,

llt Will be noted that the cab signal lamps l2, il and 5laL are not adected by the restoring of relays yand .lb byf'anybralre application. lhe relay l0 are still subject to their two conflicting controls, the polarized relay l speed has or has not been brought Within theY Tijn required limit, par I 5l?.

ilarly .lamps il and I llnyie'vsr the foregoing explanations the,`

actionv of any occupied code will be immediately clear. @ne of the relays 3l releases its armature permanently or until the occupied code is" succeeded by caution or clear code. 'llhe green lamp goes out per manently.z fflhe relays .l-0 e and ll llc' are counted down.. Relays l0 .e are not restored by the polariaed relay, since no effective track impulses are coming in, nor ll l by `timer T, which is disconnected at le: 'llhe 'red and yellovv lamps nent go out per` manently.

its before, and for the same reasons, the en 'ineer must at once apply his brakes or they vvi l be applied for him. lf he applies them in time (i. e., before relay @la is released), he

will avoid an automatic application. Since We are in an occupied block, i. e., one 1n which no track impulses will occur to restore Y the deenergized one of slow-acting relays 34, the string l0 e will be very quickly releasedV through to the end relay e, and vvill not be restored. -l'elloyv lamp 5l will go out and vvill not be relighted. Green light 42 has al ready gone out.

llf, as ive-assume first, the speed of the loco- I motive is beyond the lovv speed (say 15 miles lper hour) vpermitted in an occupied block,

then the string of relays lf lc will also very quickly be deenergized entirelya Without re` peating the reasoning given hereinbeforeoit can be stated that relay llc vvill be released fore relay c. v Thus red light 51 will' go out simultaneously with 5l.

`The instant green gineer should have applied the brakes. lf he thought the block being' entered -vvas a caution rather 'than an occupied block and thought his speed proper for a caution block and thus delayed his action, he is further warned by the extinction of the red and yellovir lights, and is thereafter, as before, bound to make a manual brake application in the time of grace, i. e., before relays l0a Z are all deenergized.4 llf he does not, an automatic application is made, the seal of .66' has to be broken, and be is presumably disciplined. i

' Let us assume that at some instant after green light l2 vventout and before Za fell, he did make a manual application of the brakes.

not affect the above description of the functioning ofthe greener yellow lamp,'but does light l2 vvent outthe en- 1' l permit timer il to restore periodically the string of relays ll ll by the circuit from ground through Wiper t, conductor 80a, righqt-` hand contact of relay ll, conductor 79a, righthand 'Winding of relay ll to grounded battery. This establishes a condition in which interruptei' counts down one byone (sin to a lamp '51 will go out, briefly, it may be, and- .light up again. When the speed is suliciently reduced, the interrupter will each time fail to Vreach relay Ia before the timer restores thestring, and red lam'p 51ik will burnsteadily. lV-hen this signal is observed,i. e., green and yellow lamps both out-and red lamp the engineer knows he isl in an occupied7 (or a stop) block but running within prescribed speed limits, and he may take olf .the brakes, and keep them olf provided he does not speed up,v too much. If he accelerates a little too much, the lred light will be extinguished very-briefly repeatedly.y If he Vaccelerates still more itwill go out andlstay out. Both are warnings to apply the brakes again at once under the usual penalty of an automatic application.-

It will be clear from the above what will be the conditions when-the engineer enters an occupiedi block at a speed within the allowed limit. lThe green and yellow lights will go out and the red light will burn. The

' will be repeatedly counted down to some point track impulses), the circuit through 67 and 40' to a change of code indication -in thentrack.4

short of Ia and set up" again by timer T.. Relay I will hold the time of grace .relays 40 Zl and hence the solenoid 53 all energized. Y

When the code-changes either to caution (slow track impulses) or to clear (qhick 39 whereby the relays 34 reenergize relays 4-0 z will be found available, being held closed at theleft-hand armaturerof relay Ic. Thus the' proper lamp response will be made If such change is,to caution, the green light lights up for a second every code interval, B. The relays 40 .e are all energized at the same intervals, also I .Ic; the interrupters 45 and 45a deenergize, respectively, these two strings of relays as far down as they have time between track impulses. And

the yellow lamp'burns, unless of course,'tl1e speed is still above that permitted in a caution block. The red light also burns unless thespeecl is excessive. The operation is'now,

therefore, exactlyfas `described above under caution .block Ioperation.

-Ivf such code change vis from occupied to clear, the two slow-release quick-acting relays 34,Willboth become and stay energized..

This lights the green lamp steadily. The relays 40 z andI Ic will all be energized. Yellow and red lights burn.- Everything is again as described above under clear block operation.

burning,

l shaft of reverser 84; is preferably geared, in

My invention, however, may be variously practiced, as was suggested above, and among other variations S maybe a tran'sformer'or set of transformers or of power lines selectively delivering (conductively or inductive- 1y) into the track circuit series of current waves of substantially' the characteristics shown in Fig. Q'and of the proper sequence, polarity and timing to constitute the required code for the conditions of the moment. In other Words, the code'currents may be produced at a distance, insteadvof locally, by a battery and interrupters as shown andas I am` aboutvto describe in detail, transmittedv over wires to the different controllers 6 along Athe roadbed', and .selectively fed by them to.

the track circuits-in substantially the same manner as, in Fig. 11, I feed the locally generated codes.

In controller, G, vshown in Fig. 1l surrounded by a dotted line, 69 is an interrupter or rather a reverser or pole-changer fed by the `battery leads 7l`, 72, respectively, -land through Wipers 7 3 and 74e bearing on collector rings 77 and 78. ,Wipers 75 and 7 6 bear alternately on the -lland the conducting segments .of reverser ring 79. The insulation between these segments is wider than the bearing surface of and 76 so that they are both simultaneously insulated from the source S for a very brief instant. Vipers 75 and76 and the leadsv 8l land 82 therefrom thus deliver. for a brief period a supply of steady current alternating in pqlarity rather than ordinary or sine wave alternating current. The frequency of the alternations is determined by the speed of'shaft 83 which I have l marked fast in the drawing. Revel-ser 69 produces.cle ea`lrr7 codes.

\ Shaft 83 may be driven by any suitable motor, e. g., an'` electric motor drawing 'energy fromfsource S, and this motor must have quite constant speed. A smallD. C. motor vwith governing means to compensate for voltage changes would be suita'rble. 'Shaft' 83,

that the speed is such as to produce the caution code'. It need not be further described Conductors 85 and 86 then deliver slow reif versed direct current according to the code of Fig.- 5 and with wave forms substantially like those of the upper line of Fig. 3. The

waaien a very close adjustment ot' the widths' of the insulation and of the'wipers, or a relatively latter is preferable and obtainable by making the diameter of 79 large in relation tothe width of wipers 75 .and 76.

llt is noteworthy, however, that using as l do yin Fig. 10 an unbiased polarized relay, this relin'ement is not necessary.. llt, some time after current in the one direction has been interrupted, currentin the opposite direction is sharply set up in the track, the

result so far as the receiving circuit on the locomotive is concerned is merely that two impulses ot the same polarity'are received in rapid succession. The first will have practically always the higher voltage and the shorter duration `and will operate the polarized relay.A The second will have no edect.

Moreover, other forms of reversing de' vices, with a quick spring or magnetic act-ion, are well known and can be equally well used. The commutatorua'nd carbon 'brush type l find preferable :trom the standpoint ot general durability and reliability of contact. lin

` any case, should either reverser slow up, stick,

break contact, or be short-circuited and below the fuse F, the code Jfed to the track will enforce a lowerftrain speed, or produce theetfeet of stop'code.

87 isa biased polarized relay, and it is shown biasedby a spring 88, though it may be biased a vtrain enters the block by unbalanced polarizing Hun, and, for thel simplicity othepdrawing only, it is shown with a permanent polarizing magnet 89 instead of a polarizing winding. lts armature is` grounded. lt is connected acrossthe entering end of block or section oi traclrv No. 1. llt constitutes, together with conductors 91,92 the circuit connection oflFig. 1 which completes the'traclecircuit tor this bloclr. The

through the windings of relay 87, but when the Ytra'clr circuit is closed through the wheels and axles thereof, ln Fig. 11, though the rear or entering ends of two .blocks4 Nos. and 2.are visible, the drawing of relay 87' has not beenrepeated for-block No. 2, and conductor-S91?, 92 lead- 'ing to another and, to be imagined, similar polarized relay across block No. 2, are merely` indicated ending in arrows. This is'also the treatment ofthe `two visible front or enit'ends tien to shatt'83, to the same larlti'e surface speed of reverser ring 79. The

track circuit in each block is normally closed' of bloclrs Nos. 2 and 3, and of the conductors 93, 94 or 93, 94a feedingthemfrom code controllers 6.. Only controller 6 feeding bloclt conductor 97. Relays 98are shown equipped with heavy copper collars to indicate slowness. They are `preferably of a mechanically retarded type, because of the expense' of making an electrically retarded relay as slow as these arelequired to be, if the cau` tion,7 interval B is taken'of the order of seven seconds as'suggested above. The preferred retardation, it'such long code intervals are chosen, is of a 4well-known type involving angular acceleration ol"a balanced mass or flywheel by a relatively weak-force applied by the attracted armature, and is such that the energy of successive impulses is largely stored in the mass. A weak spring or light weight opposes the armature attraction. li, however, more rapid caution codes are chosen, electrically sluggish relays are suitable, vand can be producedrat reasonable eX- pense. l

When, therefore;v either clear or cau. tion code is in-bloclr No. 1, extra slow relays 98 attract and hold attracted theirarma tures and a circuit is closedfrom battery Ithrough their armatures in series, through-.conductor 99 and the winding of relay 101, to ground. Relay 101 attracts its two armatures and connects the leads 81, 82 which yield clear code, to the traclg feed wires'93 and 94 of block No. 2.k Thus clear or caution in one. block establishes clear in the block behind.

Let us assume that in block No. 1 the stop code is set up. As the polarized relay 87 is,

. more or less fortuitously, shown biased torespond to positive current, it is necessary to choose as the stop code to cooperate there with the one shown on the `third line of Fig. 9, i. e., continued steady current in thev posi tive direction. Oppositely biasing the relay 87 would require using for stop code a continued negative current. Assuming then a continued positive How in block No. 1 and therefore through conductors 91, 92 and the windingV of relay-87 the right-hand extra slow relayf98` is held energized, but the lefthand relay releases Aits armature. llt is readily seen that a circuit is thus cl'o'sed, enenl gizing relay 102 and thereby applying to feed wires 94 and 95 the caution code always in leads-85 and 86.. Relays 101, 102`ai1d 103 must be relatively quick Ato release and slow to operate in order'that two codes shall not be fed simultaneously with resultantvprobable short circuits. We-now have stop code in bloclr No. l, causing caution code to be ted -to block No. 2.y This, in turn,l willl cause clear code to be fed in block No. 3.

Assume now'that block' No. 1 is occupied i and that theentering'end is therefore currentless. 'Relay ISZlllies as shown in Fig. 11. Relays 98 stay as shown anda circuit isset up energizing relay 103 .andxfeeding steady current in the positive direction from battery leads 71, 72 to feed wires 93, 94 and to the track of block No. 2. This is the sto code chosen. vVile thus .have the occu ie block No. 1 setting up stop 5 codein b ock No.- 2.

`No. .-5, and so on'.

This in'turn, as detailed above, sets up fcauf l tion cod'e in block No. 3,'Which again sets up clear .code in blockv No. 4. And clear code inblock No. 4 reproduces itself in block 'IYliat I claim is:

1. In a trainlcontrol system, avehiele,a

timing device on said vehicle constantly operating independently of track conditions, a set of counting relayson said vehicle, means for 'operating said'relays in one sense under the controlof a wheel ofrsaid veliicle, and

means controlled by said device for operating said relaysin the opposite sense.A

2. In a-traincontrol`system, a vehicle, a. set of counting relays on said vehicle, means controlled by a wheel of said vehicle for successively deenergizingV said counting relays,

and a uni/formly operating timing device on` said vehicle for successively energizing said relays independently lof track conditions.

3. In a train control system, a vehicle, an" interruptor operated by said vehicle, al set of.

countin relays onsaid vehicle, circuits con trolled y said interruptor for successively deenergizing said relays, a timing device on said vehicle uniformly operating independf entl of-track conditions, and circuits control ed by said timing device for successively energizing said counting relays.

4. In a train control system, a vehicle, an interrupter operated by-a Wheel of said vehicle, a set of counting relays on said vehicle, an energizing circuit` for the first countin relay, energizing circuits successively closed for the other counting relays upon the energization of said first relay, locking circuits for said relays controlled b said interruptor,

and an interruptor on sai vehicle constantly l operating independently of track-conditions for controlling the energizing circuit of said first counting relay.

5. In a train control system, a track section, a vehicle movable thereon, .an interrupter operated by a wheelof said vehicle,- a set of countingrelays on said veh1cle,'means for producing in said track section codes of electrical impulses corresponding to 'different operating conditions for said track section, an energizing circuit for the first counting relay closed in response to a certain code, energizing circuits successively closed for the 'other counting relays upon the lenergization 1vehicle constantly j operating independently of trackcond'itions controlling the' energiz- `ing circuit of the first counting relay;

of the first relay, a" locking circuit for. each one of said counting relays controlled by said interruptor, a -visua-l signal actuated .upon the deenergizat'ion of afeertain one of said counting relays, and an interrupter on said 6. In a traincontrol system, a track, a vehicle, means to produce track indications, means on saidvehicle controlled by the'track indications to limit the speed of said vehicle to one limit, a device on said vehicle marking off uniformintervals'of time, a. device on said vehicle marking off uniform distancesg .of vehicle travel,and means cooperatively controlled by said llast two vmeans to limit the speed of said vehicle to another and lower limit. i.

7. In aA train control system, 'a track, a vehicle, -means partly on the ground including said trac-k and partly on said vehicle to exert vehicle speed-limiting control under one set of conditions, andmeans Wholly on said vehicle to e ert vehicle speed-limiting 'saA control under an'ot erset of onditions, said last mentioned means comprising a timin device constantly operatin independently o track conditions and inc uding means for continuously 'comparing the timing of said devicewith the speed ofthe train and for comparing the timing of sai the track conditions.

8. In a train control system, a track', a vehicle, means partly on said 'vehicle to give speedflimiting indications when said vehicle exceeds a limlting speed for one set of con- -ditions, and means Wholly on said vehicle`to device with j give speed-limiting indicationswhen said veset of conditions, and means wholly on said Vvehicle to give speedelimiting control when said ,vehicle exceeds a lowerv permissible limiting speed for anotherset of conditions said last mentioned means comprising'a timing device constantly operatingindepen'dently of trackconditions and including' means' for continuously comparing the timing of said device with the speedl of thetrain and for comparin the timing of said device with the track con tions.

10.l In-a train control system', a track, a

izo

vehicle,brakes on said vehicle, meansincluding said track to apply saidbrakes when said vehicle exceeds a permissible limiting speed for one set of conditions, and means wholly `on said vehicle to apply 'said brakes when said Vehicle exceeds a lower permissible limiting speed for another set of'conditions, said latter means Icomprising an impulsor of frequency proportional to the speed ofsaid veliicle, `an impulsor' of `uniform independent Y frequency-and an electromagnetic register p' including aseries of relays oppositely op'erated by said twoimpulsors and an electromagnetic brake control means controlled'byA said register. 4

11.y In a train control system, a track, a vehicle, brakes on said vVehicle and at least one speed-limiting device wholly on said vehicle comprising a clironometer, an odometer, a. comparator means oppositely controlled by the two and determining the operation of said brakes when, predominantly controlled by said odometer, and abra-ke operating 4means including another odometer to delay operation of saidbrakes for a definite distance of vehicle travel after said comparator means hasdetermined-the operation of said brakes.

12. In a train control system, a track, aV

vehicle, brakes on 'said vehicle,at least one jfspeed-l1m1t1ng device whollyon said vehicle comprising a circuit closer of a constant speed,

an interrupter of a speed dependent upon the v vehicle s eedfa comparator means comprising ane ctromagnetic counter registering revolutions of said interrupter and returned tofn'o'rmal at constant time intervals by said "uitfclosen'and-a brakefapplying means to apply' said vbrakes when the counter of said com" arator means registers a predetermined 40 num er of'revolutions of said interrupter before it isreturned to normal by said circuit closer.` l v13. In a train control system aftrack, means for impressing on said trackv currents of dif-l ferent characteristics each corresponding to a maximumallowable speed for said vehicle, a registergdevice jointly controlled in accordance with said-currents and in accordance with the vehicle speed, a second register device jointlycotrolled in accordance .with said currents andin. accordance with a dey vice, having. a oo ant speed, each of said registers corresponming to a diierent range of vehicle speed-arid effective to control the automatic braking of said vehicle when the corresponding speed l range is exceeded.

14. In a train control system a vehicle, a'

registering device on said vehicle to be opvehicle, a second register device also operated in accordance with track currents and released in accordance with the speed of saidvehicle, means for effecting the release of said second register at a derent rate from the release fa constant speed device.`

erated in accordancewith track currentsand, released in accordance with the speed of saidv Y, i i

of said first register, and means for comparing the release of said second register with 15. In a train control system,/a trackway, means for applying to said trackway cur- .-0 rents corresponding to diii'erent operating conditions. in said trackway, a Vehicle, a irst set of counting relays on said vehicle, means for controlling said counting relays by the track currents, means controlled awheel of said vehicle for simultaneously controlling said first set of counting relays, a-second set of counting relays adapted to be 'controlled by the track'currents, other means controlled by a wheel of said Vehicle for simultaneously controlling said second set of counting relays, and a uniformly operating timing device on' saidve'hicle for controlling the sec-- ond set of counting relays.v

16;"In a train lcontrol system, a trackway, means for impressing on said trackway electrical impulses corresponding to different operating conditionsinfthe trackway, a vehicle, a first set of counting relays on said vehicle adapted to be selectively energized by the track currents, a second set of countingrelays on said relays also adapted to be selectively energized by the track currents, means for comparing the energization of each of said sets of relays withtne speed of the train, andv f a uniformly operating timing device or1controlling the energization 4of one of said sets of counting relays.

17 In a train control system, a trackway, means for impressing on saidtrackway Ae'1e' 100 trical impulses 'corresponding to different'operating condtions in the trackway, a first stepby-step device adapted to be operated under control of the track currents for one set of track conditions,and a second step-by-step device adapted to be also controlled by the track currents for another set of track conditions, an automatic brakingvmeans for said vehicle adapted to be operated when either of said step-by-step devices has beenoperated to a ,11.0 predetermined extent, and a uniformly oper-l ating timing device on said vehicle for controlling the extent of operation of one of said step-by-step devices.

18. In combination on a railway train, a series of relays, means for causing successive re- April-,1926. l ARTHUR. ADAMS. 

